Automatic circuit-breaker.



n J, L. MITCHELL. AUTQMATIG CIRCUIT BRBAKER. APPLICATION FILED NOV. 1.4,1Q12.

Patented July 21, 1914 1.-' L. MITCHBLL-- AUTOMATIC CIRCUIT BRBAKER.

AEPLICATION FILED NOV. 14', 1912.

1,104,439. y, 1 A Patented July 21,1914.

Iz SHEETS-SHEET 2.

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To it nitty/concern Be.y it known thatiI, JAMES L. MITCHELL, acitizen.yof,j the United States, residing at Santa aula,vl in 'thacounty of. Ventura and StateofyQaliforni .,have invented certainnewaand. .useful.. ,Improvements in Automatic.Circuitslreakersg and I dodeclare the following to bea full, clear, and exact desc'ription of` theinvention, such as will enablegiothers skilled. in the art to which it vappertains -tomake and use 4the same.

This invention .is an electrical circuit breaker, andits object is to somodify the constructionaof anioiidinary knife switch or circuit closerthatthe same shall be thrown openand theicircuit yjbroken in the eventthat thei,..current xbecomessuddenly eitherexcessiverf'ora'(eXtreInely.weak, byireason of an 'overloadf or yanunderload, or in the event thatf-xthef circuit is entirely broken atsome point.

The invention consists in the specific construction -jof the circuitbreaker whereby this general-ideaiscarried out, all as hereinafter moreyfully described and claimed, and as showninthe drawings wherein- Figure1 is a front` elevation and Fig-. 2 a side elevation of this devicecomplete. Fig. 3 isa planeview4 thereof. Fig. 4 is a detail in sideelevation showing the trigger as tripped, and Fig, 5 is an enlargedperspective detail ofthe trigger alone. Fig. 6 is a perspectivedetailgof the main triplever, and Fig. 7 a similardetail of thesecondary In the drawings Ifhave shown my invention as applied'toanordinary three-blade knife switch whose blades B are pivoted at P to asupport S and passed between spring terminalsto make ,the lcircuitcomplete at thepointsv T when.. the switch stands upright, and the upperends of said blades are connected .by aninsulated bar I carrying ahandle H. :i

No yclaim for novelty is laid on this switch' orfcircuit Pcloser, asitis the ordinary type now in common use, and it is obvious that myinventiony could.,be applied to 'switches of thischaracter having agreater or lesser number of blades', .or to other types of switcheswithout departing from the principle involved.

Coming now invention, the support framework v1; suitably braced as tothe details of the present S carries a horizontal at 2 and piercedwithan opexing 3 through which I ,STATES PATENT FFlCE. y It.,im:regadera".cn'senreganm. neuronale y miroiterie item1-amena y n p Specification QfLettrSRateet PatentedJuly 21,1914. `Application inea November 14;'1912.sep-innemen;

passes 'an arcuate rod 4 which is secured at its upper end as at '5 tothe handleI-I .and is headed at its lower end `as at 6', and betweensaid head and the lower side of the framework 1 an expansive spring 7 iscoiled on said rod so that its tendency is' to dranT the same downwardthrough the opening 3 and to throw the switch open. owever, any

otherV suitable"'mechanism might be em- 55 ployed for holding the"switch normally open, and theillustration of this form must' thereforebe taken 4as typical only. At a suitable point said rod is provided witha notch 8, so disposed that it stands just above the framework l whenthe switch is closed as seen in Fig. 1.

In Fig. 5 is best shown the form, of triggeil which I preferably employin this de- The same comprises a block-shapedms vice. body 10 having anose 11 at its front end vadapted to engage said notch 8, and itisimportant that the nose projectto one side from the upper corner ofthe block, while the rear lower corner of said block is progo vided witha notch 12 adapted to be engaged by the tripping mechanism hereinafterdescribed. yThe trigger is also provided with 'a handle v13) by meansolf-which it may be set. This trigger is pivoted at 14 within a 85snitable bearing 15 mounted on the frame| 1 and at such 'point (see Fig.4) 'that the descent of the rod 4 under the impulseof the spring 7 willcarry the rnotch 8 downward and with it the tip of the nose 11 so 90that the trigger turns on its ivot 14 if it be free. On the other hand,i. some mechanism engages the notch 12 at the rear of the body 10,' thenose cannot descend and therefore the rod 4 will be held elevatedagainst '95 the tendency pf its spring 7. Coacting with said trigger l1sa tripping mechanism consisting of a trip lever 20 whose nose or frontend 21 is adaptedto enga e or to be engaged with of the trigger israised. To this end the lever 2O is pivoted at 2 4 at a suitable point,preferably within the same bearing 15 which carries the trigger; andtheseelements are shown engaged in Fig. 1 and disengaged in 105 Fig. 4.The rear end of the trip lever is longer and heavier than its front endor nose 21, and is slotted as at 22, this end 23 preferably overlyingthe frame asbest seen in Fig. solenoid 25 whose floating core 26 carriesan upright pin 27 which rises through the said notch 12 w en the nose 11100 3. Supported lby said frame is a 11o :trame and projects throughsaid slot 22, and on said pin beneath the rear end 23 of the lever 2O isixed a collar 28 or similar device so that. when this solenoid isenergized and its core rises, the pin will rise and the collar 28thereof will lift the rear end ot the lever 2O.v The obvious result ofthis action is that the nose 21 disengages the notch 12 in the trigger,and the latter may fall to theposition shown in Fig. el so that the rod`l can descend, and the switch is thrown open under the expansiveinfluence of the spring '7. l

The tripping mechanism for the trigger also by preference includes asecond trip lever 30 whose nose 31 is its longer and heavier end andstands beneath the slotted rear end 23 of the main trip lever Q0. Thissecond or supplemental trip lever is pivoted at 34 in a suitable bearing15 carried by the frame 1, and its rear end 33 is slotted as at32.Carried by said trame is a coil 35 whose core 3G is byl preferencerat-her heavy, and this Acoil rises through the frame and extends.loosely through the slot 32, above which it is provided with a collaror similar device 3S. By preference the secondary lelver 30 is disposedat right angles to the main lever 2O as best seen in Fig. 3, althoughthis is a detail of construction dependentupon the shape of parts. l

The action of this device will now be clear when it is understood thatboth coils 25 and 35 are 'included in the circuit which passes throughthe switch, although the wiring is not shown in the drawings. Then theswitch is closed and the parts stand at rest, they remain in thepositiony shown in Figs.

11, 2 and 3 asv long as the current is flowing and is normal. It now asudden overload is thrown onto the circuit for any reason, the core 2Gwithin the solenoid Q5 rises, the collar QS lifts the rear'end 23 of themain lever 20, and its front end or nose Q1 is borne downward outofengagement with the notch 12 of the trigger as seen in Fig. 4, so thatsaid trigger drops and disengages the notch 8 of the rod l and thespring 7 expands and throws the switch open. There is no provisionforlperinitting the switch to remain closed, even though it is set byhand, so long as the overload continues in circuit; but when theconditions are restored to normal, the switch can be closed by raisingits handle H which brings its notch S into position to be rengaged bythe nose.11 of the trigger, the latter being actuated by its handle 13and the nose 21 of the lever 20 being rengaged with the notch 1Q. lViththe conditions at normal, if the circuit should be broken from any causethe heavy core 36 in the coil 35 will fall and its collar 38 will .beardownwardon the rear end 33 of the secondary lever 30, with the resultthat the nose 31 of the latter will rise. As said no sc notch in saidheel when the 'trigger ia underlies the rear en( 93.01? the niain leverQ0, the latter will move and the action above described will berepeated. To be more exact, whenever the voltage in the circuit falls tosuch a point that it no longer sustains lthe rather heav;1 core 3G, thesecondary trip lever 30 is moved; this moves the primary trip lever Q0.and this in turn trips the trigger. On the other hand, whenever thecurrent in the circuit is increased to such an extent. that the core 96in the solenoidl'is caused to rise, its collar QS actuates the mainlever 2O with the result desired, but in moving it does `not move thesecondary lever 30. So that it will be seen that the action of the twocoils o r solenoids is independent, while producing the unitary result.I might say that while I have shown a solenoid and core,

-it is possible to use electro-magnets at these points and substitutearmatures for the levers shown, so'long as the armatures are themselvesmounted on levers which produce the result of disengaging the heel ofthe trigger and permitting its nose to Jfall and release the notch 8.are not ilhlistratcd, because the modifications of which the device issusceptible will be clear to any electrician. rlhe materials andproportions of parts are not essential to the successful operation ofthe whole.

ll'hat is claimed as new is: f

1. The combination with a frame having an opening, a notched rod projeci`ig through the opening and headed, and a spring cci thereon betweensaid head and frame; ot' a tri` wer movably mounted on said frame withits nose adapted to engage said neL h and its heel provided with a notca pivoted lever whose nose is adapted to en-' 'age the 55k" and a coilwhose core is connected with "he lever and moves the latter to diseng y'trigger. when the coil is energized.

l2. The combination with a notched rod, and means tending to move itlongitudif nally; of a pivoted trigger having its nose vadapted toengage said notch and its heel provided with a notch, and trippingmechanismv including a lever whose nose is adapted to engage the notchin said heel when the trigger is set, a pivot for said lever, an uprightcoil, anda core therein carrying a collar contacting with the rea` armorsaid lever and adapted to actuate the latter. to disengage said triggerwhen the coil is energized.

3. The combination with a switching mechanism normally heldunder tensionand including a rod; of a trame having a hole through which said rodmoves when the switch is thrown', av trigger pivotcd on the frame andhaving a nose adapted to engage said rod when the switch is closed, ahandle on said trigger, a trip for holding said trigger with its no'sein engaging position, and

These suggestions a coil'for causing said trip to release said trigger-when the conditions in the circuit being controlled .become abnormal.

4. .'llhe combination with a switch normally held u'nder'tension, and arod carried by its handle; of a frame through which the rod moves whenthe switch is thrown, a trigger consisting of a block-shaped bodypivotally mounted in a bearing upon said frame and having a noseprojecting forward from one upper corner and adapted to enga ge saidrod, the bodyalso having a notch in its rear lower corner, and trippingmechanism for holding said trigger with its nose in engag- .ingposition. l

5. The combination with a switch, aframe having anv opening, and a rodprojecting from the switch through said opening and having a notch; of amovable trigger whose noseis adapted to engage said notch and whoseheelis notched, a pivotal support for this trigger on said frame, a triplever piv-l oted between its extremities o'n said frame with its noseadapted to engage the notch in the heel of the trigger when the latteris set, and electrically actuated mechanism -for moving the rear arm ofsaid trip lever when the conditions' in the'circuit being controlledbecome abnormal.

6. The combination with a switch,aframe having an opening, and a rodprojecting from the switch through said opening and having a notch; of a,trigger pivoted on said frame with its nose adapted to engage saidnotch, a lever pivoted between its eXtremities on said frame with itsnose engaging said trigger to hold it set, the rear arm of said leverbeing slotted, a solenoid carried by said frame and in circuit with thevcircuit being controlled, a floating core within said solenoid, a pinrising therefrom and projecting loosely through the frame and the Vnotchin the rear arm of the lever, and a collar fast on said pin beneath saidarm, for the purpose set forth.

of said first lever, an over-load coil controlling the rear arm of saidfirst lever, and an under-load coil controlling the rear arm of saidlast lever.

8. The combination with a frame, and a trigger thereon; .of a leverpivoted on said `'frame with its forward arm engaging said trigger whenthe same stands set, a second lever pivoted on said frame with itsforward arm beneath the rearward arm of said first lever, an over-loadcoil carried by the frame beneath the rear arm of said rst leverconnections between such arm and Ilthe core of this coil,-an underload coilcarried by said frame beneath said second lever, and connections betweenthe latter and the core of this coil, for the purpose set forth.

9. The combination with a trigger; of a pivoted lever with its forwardarm engaging said trigger and its rearward arm slotted, a second pivotedleverwith its for` ward arm engaging beneath the slotted arm of thefirst lever andits rear arm slotted, a solenoid having a floating core,a pin rising therefrom 'through the -slotted rear arm of the firstlever, a collar on this pin beneath said arm, a coil beneath the reararm of the second lever, a weighted core therein rising through the slotof such lever, and .a collar on the core above said arm, for the purposeset forth. l

ln testimony whereof I have hereunto set f l my hand in presence of twosubscribing witnesses.

CoRA L. Grunn, H. N. SNYDER.

